Derivative Instruments (Income Statement Disclosure) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Not Designated as Hedging Instrument [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (362)	$ 231
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Gains (losses) included in operating revenues [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(4)	137
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Gain Loss Included In Interest Expense Member
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(19)	45
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Gain Loss Included In Interest Expense Member
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(326)	59
Reclassification out of Accumulated Other Comprehensive Income [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Gain Loss Included In Interest Expense Member
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Interest Expense	(1)	(1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Gain Loss Included In Interest Expense Member
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Interest Expense	(12)	(9)
FPL [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Gains (losses) on commodity contracts, recorded as regulatory assets and or liabilities on the balance sheet due to regulatory treatment	$ 2	$ 4